1. Field of the Invention
The present invention relates to adjustable beds and, more particularly, to adjustable medical beds providing a plurality of height adjustable positions.
2. Description of the Prior Art
Beds for patients/residents requiring long term care are designed to meet a variety of needs, including designs which are adapted to accommodate particular needs of patients/residents, as well as to facilitate medical procedures provided to patients/residents on the beds. One function required of such beds for long term care patients/residents includes the ability to position a patient support surface to different vertical positions relative to the floor. For example, during normal use of the bed by the patient/resident, it is desirable to have the bed located at a convenient level for the patient/resident to easily enter and exit the bed. Alternatively, it is desirable to have the patient supporting surface at an elevated position to locate the patient/resident at a convenient height when it is necessary for medical personnel to interact with the patient/resident, such as during an examination or performance of a medical procedure with the patient/resident on the bed.
Among the requirements for such height adjustable beds, is the necessity to provide for easy actuation of the bed while minimizing operator input to the bed controls. In addition, it is desirable to provide a bed which provides both convenient vertical and horizontal positioning of the patient support surface for the purpose of access by medical personnel.
U.S. Pat. No. 4,472,845 (Chivetta et al.) discloses a height adjustable hospital bed which is vertically movable from a lowered position to a raised position. This bed is shown mounted to a frame which is supported on a plurality of casters, and a movable upper frame is supported for vertical adjustment relative to the fixed frame wherein the movable frame is located above the fixed frame in the lowermost position of the bed. Accordingly, the overall height between the floor and the patient support surface for this bed must accommodate the distance required by the casters and fixed frame.
U.S. Pat. No. 5,317,769 (Wiesmiller et al.) discloses a bed similar to that of Chivetta et al. in that a height adjustable hospital bed is disclosed including a vertical bed adjustment mechanism supported on a lower base frame wherein the lower base frame is supported by a plurality of casters. In this bed also, the minimum vertical height of the patient support surface is limited by a vertical dimension including the casters and base frame, above which the height adjustment mechanism operates.
Accordingly, there is a continuing need for a long term bed which provides a wide range of vertical height adjustment for a patient support surface, and which also provides for convenient horizontal positioning of the patient support surface. In addition, there is a need for such a bed wherein the vertical height positions may be preselected in accordance with predetermined anticipated needs of a patient/resident supported on the bed.
The present invention provides a height adjustable medical bed, particularly for use with patients/residents requiring long term care. The bed includes a support surface for supporting a person in a supine position, and a main frame supporting the support surface and defining head and foot ends for the bed. The main frame is supported by support members including a head end member and a foot end member having upper ends pivotally attached to the main frame. The head end member includes a lower end supporting rollers defining roller engaging surfaces for rolling on a floor surface. The leg end member includes a lower end including a non-rolling or frictional engaging surface for engaging the floor surface in a substantially stationary position. The head end member and foot end member are each actuated by a drive means comprising a motor wherein the motors are connected to a control system whereby operator actuated switches are used to control actuation of the motors. The motors may be actuated to move the patient support surface to different horizontal and vertical positions as well as to Trendelenberg and reverse Trendelenberg positions.
A sensor is provided for a sensing the position of the frame as it is moved toward a lowermost position and for automatically terminating downward movement of the frame at a lower intermediate position adjacent to and spaced from the lowermost position. The lower intermediate position provides a preferred day position for the bed which locates the patient support surface at a convenient height for entering and exiting the bed, and the lowermost position provides a preferred night position for the bed located closely adjacent the floor.
The lower end of the foot end member is additionally provided with a roller engaging surface located adjacent to and in fixed relation to the frictional engaging surface. The roller engaging surface is adapted to move into engagement with the floor surface, and the frictional engaging surface is adapted to move out of contact with the floor surface, when the frame of the bed is moved to an uppermost position. In particular, a sensor is provided for sensing the position of the frame as it approaches the uppermost position and for signaling the control system to terminate upward movement of the frame at an upper intermediate position adjacent to and spaced from the uppermost position. The upper intermediate position corresponds to a position for locating a patient/resident on the bed at a convenient position for medical treatments and examination. In this position, the frictional engaging surface is in contact with the floor and the roller engaging surface of the foot end member is out of engagement with the floor. Subsequent upward movement of the bed results in the roller engaging surface of the foot end member moving into rolling engagement with the floor surface to facilitate horizontal rolling movement of the bed to a new location.
Therefore, it is an object of the present invention to provide a long term care medical bed capable of vertical movement and including intermediate stop positions between uppermost and lowermost patient support positions.
It is a further object of the invention to provide a vertically adjustable bed including pivoted head end and foot end support members wherein the foot end support member includes a frictional engaging surface for engaging the floor at a stationary position and the head end member includes a roller member for rolling across the floor surface.
Other objects and advantages of the invention will be apparent from the following description, the accompanying drawings and the appended claims.